Usually, when the two-factor authentication is used, a verification code is sent over another communication channel, mostly SMS. User is then required to retype the verification code from smartphone to PC.
Ultrauth consists of two parts, one for smartphone and one for PC. The smartphone app is running on Android, reads SMS and extracts authentication codes and transmit them over the sound to PC. The PC part extracts information from sound and grant or deny access, based on code authenticity.
The app can detect 2FA messages and extract authentication codes
The code is then encoded and emited through the device speaker
The browser part of the app listens and waits for a code
After the code is recorded, user is authenticated and verified